Supplementary Material for: Electrode tract oedema in stereo electroencephalography (SEEG)

Introduction – Stereo-electroencephalography (SEEG) is a safe and effective procedure for the identification of the epileptogenic zone to guide epilepsy surgery. Electrode tract oedema in SEEG is poorly understood. This study reports on its incidence and its clinical and biochemical correlations.
Methods – The presence of oedema along the electrode tract on patients after removal of SEEG electrodes was recorded and described. The trend of serum inflammatory markers of patients with and without oedema were compared with non-linear regression using 2nd and 3rd order polynomial models and the extra sum-of-squares F test.
Results – 79.2% of patients had radiographic oedema. Two radiographic distributions of oedema are described. No statistical differences were found between the trends of serum inflammatory markers of patients with and without oedema. 8.6% of patients had isolated fevers of non-infectious origin. 11.4% of patients had subclinical haematomas. No patients had infective or thromboembolic complications.
Conclusions – Radiographic electrode tract oedema is common in SEEG and runs a benign clinical course in our series.

引言 – 立体脑电图（Stereo-electroencephalography, SEEG）是用于明确致痫灶以指导癫痫外科手术的安全且有效的诊疗手段。目前针对SEEG术后电极道水肿的认知仍较为有限。本研究阐述了该水肿的发生率及其临床与生化相关特征。
方法 – 本研究记录并描述了SEEG电极拔除术后患者电极道周围水肿的发生情况。采用二阶、三阶多项式模型的非线性回归方法及额外平方和F检验，对比了伴与不伴电极道水肿患者的血清炎症标志物变化趋势。
结果 – 79.2%的患者出现影像学可见的电极道水肿。本研究描述了两种水肿的影像学分布类型。伴与不伴水肿患者的血清炎症标志物变化趋势无统计学差异。8.6%的患者出现孤立性非感染性发热。11.4%的患者存在亚临床血肿。未出现感染性或血栓栓塞性并发症病例。
结论 – 本研究队列中，SEEG术后影像学可见的电极道水肿较为常见，且临床进程均呈良性表现。